In general, an image obtained by picking up an object by means of an image pickup apparatus such as a digital camera is under the influence of distortion aberration and chromatic aberration of magnification in an optical system such as an image pickup lens. In order to suppress distortion aberration, ingenuity is exercised in lens material, or an aspherical lens is used. However, the results in a problem of an increase in design or manufacturing cost. In addition, in order to suppress chromatic aberration of magnification, many lens sets made of materials having different refractive indexes are used so that the number of lenses is large. This results in a problem of an increase in the apparatus size and manufacturing cost.
Therefore, as a solution to the problems, an image processing device has been recently used which electrically corrects image distortion generated in an optical system when the image distortion, etc. is generated due to distortion aberration or chromatic aberration of magnification.
In an electrically correcting method used by a conventional image processing device, corrected outputted pixels are outputted in a raster scan order so that inputted pixel positions necessary for correction are calculated from outputted pixel positions. However, when image distortion is large, significant deviation is generated between outputted pixel positions and inputted pixel positions. Accordingly, a large number of line buffers need to be prepared to hold inputted pixels. This involves an increase in the device size. Further, a general line buffer is formed of SRAM which is expensive. Thus, a problem of an increase in the manufacturing cost exists.